Bluetooth接続を使用してESP32から測定値を読み取る必要があるアプリ(端末)を作成する必要があるプロジェクトがあります。 私はなんとか端末を構築し、いくつかの機能を備えたボタンを追加しました。 問題は、[List devices]ボタンをクリックすると、使用可能なすべての Bluetooth デバイスが一覧表示され、ESP32 デバイスをクリックして接続するとクラッシュすることです。 マニフェストにすべての権限がありますが、まだこの問題があります。
Java
package com.example.plavi_zub_2; import androidx.appcompat.app.AppCompatActivity; import androidx.core.app.ActivityCompat; import android.Manifest; import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.bluetooth.BluetoothServerSocket; import android.bluetooth.BluetoothSocket; import android.content.Intent; import android.content.pm.PackageManager; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.view.View; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; import android.widget.TextView; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.Set; import java.util.UUID; public class MainActivity extends AppCompatActivity { Button listen, send, listDevices; ListView listView; TextView msg_box, status; EditText writeMsg; BluetoothAdapter bluetoothAdapter; BluetoothDevice[] btArray; SendReceive sendReceive; static final int STATE_LISTENING = 1; static final int STATE_CONNECTING = 2; static final int STATE_CONNECTED = 3; static final int STATE_CONNECTION_FAILED = 4; static final int STATE_MESSAGE_RECEIVED = 5; int REQUEST_ENABLE_BLUETOOTH = 1; private static final String APP_NAME = "BTChat"; private static final UUID MY_UUID = UUID.fromString("8ce255c0-223a-11e0-ac64-0803450c9a66"); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); findViewByIdes(); bluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); if (!bluetoothAdapter.isEnabled()) { Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.BLUETOOTH_CONNECT) == PackageManager.PERMISSION_GRANTED) { startActivityForResult(enableIntent, REQUEST_ENABLE_BLUETOOTH); // TODO: Consider calling // ActivityCompat#requestPermissions // here to request the missing permissions, and then overriding // public void onRequestPermissionsResult(int requestCode, String[] permissions, // int[] grantResults) // to handle the case where the user grants the permission. See the documentation // for ActivityCompat#requestPermissions for more details. return; } else { ActivityCompat.requestPermissions(MainActivity.this, new String[]{android.Manifest.permission.BLUETOOTH_CONNECT}, 44); } } implementListeners(); } private void implementListeners() { listDevices.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { if (ActivityCompat.checkSelfPermission(MainActivity.this, android.Manifest.permission.BLUETOOTH_CONNECT) == PackageManager.PERMISSION_GRANTED) { Set<BluetoothDevice> bt = bluetoothAdapter.getBondedDevices(); String[] strings = new String[bt.size()]; btArray = new BluetoothDevice[bt.size()]; int index = 0; if (bt.size() > 0) { for (BluetoothDevice device : bt) { btArray[index] = device; strings[index] = device.getName(); index++; } ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, strings); listView.setAdapter(arrayAdapter); } // TODO: Consider calling // ActivityCompat#requestPermissions // here to request the missing permissions, and then overriding // public void onRequestPermissionsResult(int requestCode, String[] permissions, // int[] grantResults) // to handle the case where the user grants the permission. See the documentation // for ActivityCompat#requestPermissions for more details. return; } else { ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.BLUETOOTH_CONNECT}, 44); } } // String[] strings = new String[bt.size()]; // btArray = new BluetoothDevice[bt.size()]; // int index = 0; // // if (bt.size() > 0) { // for (BluetoothDevice device : bt) { // btArray[index] = device; // strings[index] = device.getName(); // index++; // } // ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, strings); // listView.setAdapter(arrayAdapter); // } // } }); listen.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { ServerClass serverClass = new ServerClass(); serverClass.start(); } }); listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) { ClientClass clientClass = new ClientClass(btArray[i]); clientClass.start(); status.setText("Connecting"); } }); send.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String string = String.valueOf(writeMsg.getText()); sendReceive.write(string.getBytes()); } }); } Handler handler = new Handler(new Handler.Callback() { @Override public boolean handleMessage(Message msg) { switch (msg.what) { case STATE_LISTENING: status.setText("Listening"); break; case STATE_CONNECTING: status.setText("Connecting"); break; case STATE_CONNECTED: status.setText("Connected"); break; case STATE_CONNECTION_FAILED: status.setText("Connection Failed"); break; case STATE_MESSAGE_RECEIVED: byte[] readBuff = (byte[]) msg.obj; String tempMsg = new String(readBuff, 0, msg.arg1); msg_box.setText(tempMsg); break; } return true; } }); private void findViewByIdes() { listen = (Button) findViewById(R.id.listen); send = (Button) findViewById(R.id.send); listView = (ListView) findViewById(R.id.listview); msg_box = (TextView) findViewById(R.id.msg); status = (TextView) findViewById(R.id.status); writeMsg = (EditText) findViewById(R.id.writemsg); listDevices = (Button) findViewById(R.id.listDevices); } private class ServerClass extends Thread { private BluetoothServerSocket serverSocket; public ServerClass() { try { if (ActivityCompat.checkSelfPermission(MainActivity.this, android.Manifest.permission.BLUETOOTH_CONNECT) == PackageManager.PERMISSION_GRANTED) { serverSocket = bluetoothAdapter.listenUsingRfcommWithServiceRecord(APP_NAME, MY_UUID); // TODO: Consider calling // ActivityCompat#requestPermissions // here to request the missing permissions, and then overriding // public void onRequestPermissionsResult(int requestCode, String[] permissions, // int[] grantResults) // to handle the case where the user grants the permission. See the documentation // for ActivityCompat#requestPermissions for more details. return; } else ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.BLUETOOTH_CONNECT}, 44); //serverSocket = bluetoothAdapter.listenUsingRfcommWithServiceRecord(APP_NAME, MY_UUID); // serverSocket = bluetoothAdapter.listenUsingRfcommWithServiceRecord(APP_NAME, MY_UUID); } catch (IOException e) { e.printStackTrace(); } } public void run() { BluetoothSocket socket = null; while (socket == null) { try { Message message = Message.obtain(); message.what = STATE_CONNECTING; handler.sendMessage(message); socket = serverSocket.accept(); } catch (IOException e) { e.printStackTrace(); Message message = Message.obtain(); message.what = STATE_CONNECTION_FAILED; handler.sendMessage(message); } if (socket != null) { Message message = Message.obtain(); message.what = STATE_CONNECTED; handler.sendMessage(message); sendReceive = new SendReceive(socket); sendReceive.start(); break; } } } } private class ClientClass extends Thread { private BluetoothDevice device; private BluetoothSocket socket; public ClientClass(BluetoothDevice device1) { device = device1; try { if (ActivityCompat.checkSelfPermission(MainActivity.this, android.Manifest.permission.BLUETOOTH_CONNECT) != PackageManager.PERMISSION_GRANTED) { socket = device.createInsecureRfcommSocketToServiceRecord(MY_UUID); // TODO: Consider calling // ActivityCompat#requestPermissions // here to request the missing permissions, and then overriding // public void onRequestPermissionsResult(int requestCode, String[] permissions, // int[] grantResults) // to handle the case where the user grants the permission. See the documentation // for ActivityCompat#requestPermissions for more details. return; } else ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.BLUETOOTH_CONNECT}, 44); //socket = device.createInsecureRfcommSocketToServiceRecord(MY_UUID); } catch (IOException e) { e.printStackTrace(); } } public void run() { try { if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.BLUETOOTH_CONNECT) != PackageManager.PERMISSION_GRANTED) { socket.connect(); Message message=Message.obtain(); message.what=STATE_CONNECTED; handler.sendMessage(message); sendReceive=new SendReceive(socket); sendReceive.start(); // TODO: Consider calling // ActivityCompat#requestPermissions // here to request the missing permissions, and then overriding // public void onRequestPermissionsResult(int requestCode, String[] permissions, // int[] grantResults) // to handle the case where the user grants the permission. See the documentation // for ActivityCompat#requestPermissions for more details. return; }else ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.BLUETOOTH_CONNECT}, 44); //socket.connect(); // Message message=Message.obtain(); // message.what=STATE_CONNECTED; // handler.sendMessage(message); sendReceive=new SendReceive(socket); sendReceive.start(); } catch (IOException e) { e.printStackTrace(); Message message=Message.obtain(); message.what=STATE_CONNECTION_FAILED; handler.sendMessage(message); } } } private class SendReceive extends Thread { private final BluetoothSocket bluetoothSocket; private final InputStream inputStream; private final OutputStream outputStream; public SendReceive (BluetoothSocket socket) { bluetoothSocket=socket; InputStream tempIn=null; OutputStream tempOut=null; try { tempIn=bluetoothSocket.getInputStream(); tempOut=bluetoothSocket.getOutputStream(); } catch (IOException e) { e.printStackTrace(); } inputStream=tempIn; outputStream=tempOut; } public void run() { byte[] buffer=new byte[1024]; int bytes; while (true) { try { bytes=inputStream.read(buffer); handler.obtainMessage(STATE_MESSAGE_RECEIVED,bytes,-1,buffer).sendToTarget(); } catch (IOException e) { e.printStackTrace(); } } } public void write(byte[] bytes) { try { outputStream.write(bytes); } catch (IOException e) { e.printStackTrace(); } } } }
そして、次のようなエラーがいくつかあります。
Java
Unable to open libpenguin.so: dlopen failed: library "libpenguin.so" not found.
Java
FATAL EXCEPTION: Thread-3 Process: com.example.plavi_zub_2, PID: 18858 java.lang.NullPointerException: Attempt to invoke virtual method 'java.io.InputStream android.bluetooth.BluetoothSocket.getInputStream()' on a null object reference at com.example.plavi_zub_2.MainActivity$SendReceive.<init>(MainActivity.java:331) at com.example.plavi_zub_2.MainActivity$ClientClass.run(MainActivity.java:307)
私が試したこと：
公式の Android dev サイトで解決策を見つけようとしましたが、問題は解決しませんでした。
解決策 1
エラー メッセージによると、次の 2 つの明らかな問題があります。
1. penguin コードを実行しようとすると、ライブラリがシステムに存在しないか、システムに見つかりません。 それがどこにあるかを調べるか、インストールする必要があります。
2. 他のエラー メッセージの行番号の前後のコードを調べます。 null オブジェクトでメソッドを呼び出しています。これは、使用している参照が初期化されていないことを意味します。
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